Time for a quick aeronautical lesson: Every aircraft has an airspeed indicator. On that dial, usually in different locations depending on the type of aircraft and how it was constructed, is a bright red peg marked "V-NE".
That stands for "Velocity: Never Exceed". It's the point where, in layman's terms, the power of your engine and the speed your plane is moving at stop holding it aloft in the skies , and start tearing the plane apart in midair. In some cases, it leads to the airflow around the lifting surfaces forcing it into an uncontrollable spin or dive that cannot be recovered.